Analysis of Vocal Disorders With Methods From Nonlinear Dynamics

Abstract

Several authors have recently demonstrated the intimate relationship between nonlinear dynamics and observations in vocal fold vibration (Herzel, 1993; Mende, Herzel, & Wermke, 1990; Titze, Baken, & Herzel, 1993). The aim of this paper is to analyze vocal disorders from a nonlinear dynamics point of view. Basic concepts and analysis techniques from nonlinear dynamics are reviewed and related to voice. The voices of several patients with vocal disorders are analyzed using traditional voice analysis techniques and methods from nonlinear dynamics. The two methods are shown to complement each other in many ways. Likely physiological mechanisms of the observed nonlinear phenomena are presented, and it is shown how much of the terminology in the literature describing rough voice can be unified within the framework of nonlinear dynamics.

Acoustic Analysis of Aperiodic Voice: Perturbation and Nonlinear Dynamic Properties in Esophageal Phonation

“…Although nonlinear dynamic parameters have been applied to distinguish normal voice from types of pathological voice, [11][12] the efficacy of nonlinear dynamic measures in measuring esophageal voice and distinguishing this aperiodic signal from normal voice has not been previously analyzed. Esophageal voice was significantly differentiated from normal voice in the present study using measures of correlation dimension and second-order entropy.…”

“…[8][9][10][11][12][19][20][21][22] These types of measures have complemented traditional perturbation measurements due to an ability to describe chaotic, aperiodic voices. [8][9]11 A reconstructed phase space can be created by plotting a voice signal against itself at some time delay.…”

“…The concept of human voice production as a chaotic system has been established in recent years through computer modeling, excised larynx experiments, and human voice analysis. [8][9][10][11][12] A chaotic voice often exhibits an irregular and aperiodic waveform, poor perceptual qualities, and extreme perturbation values. Because all human vocal folds exhibit some inherent chaotic properties, nonlinear dynamic methods are useful for quantifying the degree of aperiodicity and irregularity.…”

Pulse register phonation in Diana monkey alarm calls

“…Several lines of research suggest that nonlinear phenomena are common and ubiquitous in mammalian vocalization behavior ͑Wilden et Mergell et al, 1999;Riede et al, 1997Riede et al, , 2000Fischer et al, 2000͒. Phenomena such as frequency jumps, subharmonics, biphonation, and deterministic chaos are commonly observed, usually the result of deviations from the regular harmonic vibration pattern of the vocal folds, such as nonsynchronously oscillating left and right vocal folds or simultaneously oscillating horizontal and vertical components of the vocal folds ͑e.g., Herzel et al, 1994;Berry, 2001;Berry et al, 1994;Steinecke and Herzel, 1995;Tigges et al, 1997;Neubauer et al, 2001͒. The two combined approaches are likely to yield important insights into the sound production mechanism underlying male Diana monkey alarm calls.…”

Software corrections of vocal disorders

“…It is not addivite and it is correlated with the other sub-part of the sentence one would like to isolate. In [8][9][10][11][12][13] it is shown how some of the complexities observed in disordered voices are not caused by random external input to the vocal apparatus, but by the intrinsic nonlinear dynamics of vocal fold movement. Normal phonation corresponds to an essentially synchronized motion of all vibratory modes.…”